I've been digging through benchmarks and reviews for a solid week now and there are so many options for graphics upgrades that it makes the head spin. I'm using an old 8800 GTS 640 right now and I'm looking at ~800 for a PSU and graphics upgrade. My i5 2500k and P67A-GD65 are in the mail.
Currently I'm using a 650W Rosewill PSU which I will keep for a while when the new MB and CPU get here, but I intend to upgrade it within the next few weeks (maybe). 3 HDD, 1 DVD player, 912 HAF, 6 fans. At the moment I'm using an old 19" CRT monitor (haha, yes, I know), but I'm going to upgrade to a 24 inch LCD this fall. Either way, I don't plan on doing any gaming above 1080p resolution.
When I first started searching I thought that a couple of the stock OC 560 ti boards would be good. Then I saw the little gem about the 6950s which were unlockable to 6970s with a bios update. That had me salivating for a good few days, until I realized the chances of getting a flashable card are diminishing every day.
From there I started looking at the 6870s since they aren't too far behind the 6950s and 560 tis. And with the couple hundred bucks I would save with a pair of 6870's in XF, I could get a nice SSD as well.
Annnnd.... then I wondered why not just get a 6990, or 590 gtx (if I could find one in stock). I think the poor PSU would be limping to keep up until I could afford to replace it with a better one in a few weeks.
I only upgrade about once every 5 or 6 years, so longevity is important with my builds. Right now I'm still scratching my head on the decision. I am leaning slightly towards getting a single 6990 or 590 gtx, and then picking up another one somewhere down the road for SLI or Crossfire, but then I'm not completely sure my PSU would keep up, and I'd hate to have to watch my pretty card sitting on the shelf for a few weeks while I saved up for a new PSU.
Basically, I want fluid frame rates for any game I can throw at the system on the highest settings at 1080p, and I am big on price/performance ratio.
toss the rosewill 650w. with the vid cards youre talking about (especially if crossfired) you should look at a good 750w or better psu. antec tp-III series, corsair hx/tx, anything seasonic, even OCZ would be a step up from that rosewill.